Wednesday, January 18, 2017, 3:08 PM - We saw this coming throughout all of last year, but now it's official: 2016 is now the hottest year ever recorded for the globe, quite likely going back centuries in time.

NOAA, NASA, the Japanese Meteorological Agency and the UK Met Office have all released their independent assessments for 2016, and despite small differences in the numbers from their datasets, all four agencies have come to the same conclusion: 2016 was a record-breaking year for global heat.

• According to NOAA, 2016 came in at +0.94oC above the 20th century average.
• By NASA's records, 2016 was +0.99oC above the 1951-1980 average (+1.01oC vs the 20th century average).
• JMA has 2016 as +0.82oC above the 20th century average.
• UK Met Office puts 2016 as +0.77oC above the 1961-1990 average.

The differences in these records are due to differing methods of data collection, data processing and coverage of the global temperature data, as well as which long-term average the agency uses in its data comparisons. Despite the differences in the actual numbers, all three data sets reveal the same trend of global warming.

This graph highlights the rising temperatures by plotting each year, in sequence, on the same scale. Credit: NASA/Earth Observatory/Joshua Stevens

The overall ranking, according to NOAA, now stands as so:

Credit: NOAA

This puts 2016 at the top of the list of the hottest years on record. Looking back, 1998 - a year that saw an extreme El Niño, similar to the one in 2015 - is the only year on the list that isn't from the 21st century, and the top 17 entries on the list are 1998 and every year of the 21st century so far!

El Niño helped, but not enough

The exceptionally strong El Niño of 2015-2016 certainly helped in producing the final record-setting temperatures in 2016 and 2015, but not so much that the two years couldn't have broken the records all on their own.

El Niño was a factor this year, but both 2015 & 2016 would have been records even without it. Estimate of effect 0.05°C & 0.12°C. pic.twitter.com/tRRhVbQKRw

In a NOAA/NASA teleconference on Wednesday, Gavin Schmidt, the director of NASA's Goddard Institute for Space Studies, said that looking at paleoclimate data, which reveal global temperatures back before the official temperature records began, "2016 is very likely the hottest year for centuries."

Schmidt went on to say that changing to decade-long or century-long trends, as comparing individual years becomes difficult the farther you go back, we would likely have to go back 125,000 years, to the last interglacial period, to find a period as warm as what we're seeing now.

Unprecedented 3rd hottest year in a row

Going through the yearly temperature records, there are at least a few instances where we can find two record-breaking years in a row. It happened in the early 1940s, then the late 1980s and again in the late 1990s.

2014-2015-2016 looks to be the only time we've ever seen three consecutive record-breaking years in row.

Temperature anomalies, compared to the 20th century average, from 1880-2016. Credit: NOAA

A scary number of significant climate events

In their annual global report, NOAA flagged a great number of significant climate anomalies or events during 2016

2016's toll on sea ice

As we reported earlier this month, the heat in 2016 took a nasty toll on sea ice at both ends of the Earth, resulting in the lowest annual average sea ice extent ever seen in the Arctic, and the second lowest annual average extent in the Antarctic.

Data: NSIDC. Graph by S. Sutherland

Data: NSIDC. Graph by S. Sutherland

Overall, this has produced the lowest global annual average extent on record, and things are not looking good going into the new year.

As of now, in the middle of January 2017, sea ice extents in both the Arctic and Antarctic are still running at the lowest daily levels ever seen, and unless conditions change soon, we will be seeing the lowest summer extent on record around Antarctica, and a new lowest winter maximum on record in the Arctic.

A new temperature plateau

After three years of successive temperature records set, it's highly unlikely that 2017 will be a fourth warmest year on record.

That's really no reason to celebrate, however, because it simply means that we've likely entered the next temperature plateau.

Although there has been an overall warming trend for several decades now, within that overall trend you can find periods, each spanning several years, where you can trace a flat, or sometimes even negative, trend line.

Multiple data sets, from NOAA, NASA, UK MetOffice and others reveal the same trends. Note that the uncorrected NOAA data actually shows a negative bias in the years prior to 1940. Thus, while the uncorrected data comes to the same present conclusion, it actually shows a stronger warming trend than the corrected data. Credit: NOAA/NASA

This can be seen above, in this comparison of different data sets from various agencies and organizations. Regardless of how you look at it, temperatures are on the rise, but it doesn't happen steadily. Due to the year-to-year changes in weather patterns, and factors such as the oceans capturing the majority of the excess heat, we can pick out a pattern of temperature plateaus in the record, which are often broken by an extreme record year.

We had been in one of these plateaus, from 1998 until 2014 or 2015. It was the hottest period on record during that plateau, and while the temperature trend was still on the rise, you could still trace a fairly flat line across those years (especially if you carefully pick your span of time).

The extreme spike in temperatures for 2015-2016, however, means that we've likely jumped from one warm plateau to another, even warmer one.